Re: [PATCH v7 01/26] PM / Domains: Don't treat zero found compatible idle states as an error

[Lina Iyer]

On Thu, Apr 12 2018 at 05:14 -0600, Ulf Hansson wrote:
> Instead of returning -EINVAL from of_genpd_parse_idle_states() in case none
> compatible states was found, let's return 0 to indicate success. Assign
> also the out-parameter *states to NULL and *n to 0, to indicate to the
> caller that zero states have been found/allocated.
>
> This enables the caller of of_genpd_parse_idle_states() to easier act on
> the returned error code.
>
> Cc: Lina Iyer <ilina@xxxxxxxxxxxxxx>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>

Reviewed-by: Lina Iyer <ilina@xxxxxxxxxxxxxx>

> ---
> drivers/base/power/domain.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 1ea0e25..c2ef944 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -2331,8 +2331,8 @@ static int genpd_iterate_idle_states(struct device_node *dn,
>  *
>  * Returns the device states parsed from the OF node. The memory for the states
>  * is allocated by this function and is the responsibility of the caller to
> - * free the memory after use. If no domain idle states is found it returns
> - * -EINVAL and in case of errors, a negative error code.
> + * free the memory after use. If any or zero compatible domain idle states is
> + * found it returns 0 and in case of errors, a negative error code is returned.
>  */
> int of_genpd_parse_idle_states(struct device_node *dn,
> 			struct genpd_power_state **states, int *n)
> @@ -2341,8 +2341,14 @@ int of_genpd_parse_idle_states(struct device_node *dn,
> 	int ret;
>
> 	ret = genpd_iterate_idle_states(dn, NULL);
> -	if (ret <= 0)
> -		return ret < 0 ? ret : -EINVAL;
> +	if (ret < 0)
> +		return ret;
> +
> +	if (!ret) {
> +		*states = NULL;
> +		*n = 0;
> +		return 0;
> +	}
>
> 	st = kcalloc(ret, sizeof(*st), GFP_KERNEL);
> 	if (!st)
> --
> 2.7.4